Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

A method for processing a structure. The structure is formed and includes
a substrate, a substructure having a sidewall and disposed on the
substrate, a first polymer structure disposed on the substrate, and a
second polymer structure disposed on the substrate such that the first
polymer structure is disposed between the sidewall and the second polymer
structure. An aspect ratio of the first polymer structure, the second
polymer structure, or both is reduced in a reducing step. One polymer
structure (i.e., the first polymer structure or the second polymer
structure) is selectively removed from the structure such that a
remaining polymer structure (i.e., the second polymer structure or the
first polymer structure) remains disposed on the external surface of the
substrate after the one polymer structure has been selectively removed,
wherein the aspect ratio of the remaining polymer structure was reduced
in the reducing step.

Claims:

1. A method for processing structures, said method comprising: forming a
structural configuration, said structural configuration comprising a
substrate, a substructure having a sidewall and disposed on an external
surface of the substrate, a first polymer structure disposed on the
external surface of the substrate and in direct mechanical contact with
the sidewall, and a second polymer structure disposed on the external
surface of the substrate and in direct mechanical contact with the first
polymer structure such that the first polymer structure is disposed
between the sidewall and the second polymer structure, said first polymer
structure comprising a first polymer, said second polymer structure
comprising a second polymer; reducing an aspect ratio of at least one
polymer structure with respect to the external surface of the substrate,
said reducing comprising removing an upper portion furthest from the
substrate of said at least one polymer structure, said at least one
polymer structure being the first polymer structure, the second polymer
structure, or both the first polymer structure and the second polymer
structure; and selectively removing one polymer structure from the
structural configuration such that a remaining polymer structure remains
disposed on the external surface of the substrate after the one polymer
structure has been selectively removed, said reducing having reduced the
aspect ratio of the remaining polymer structure, wherein either the
selectively removed one polymer structure is the first polymer structure
and the remaining polymer structure is the second polymer structure or
the selectively removed one polymer structure is the second polymer
structure and the remaining polymer structure is the first polymer
structure.

2. The method of claim 1, wherein the selectively removed one polymer
structure is the second polymer structure and the remaining polymer
structure is the first polymer structure, and wherein the method further
comprises: selectively removing the substructure such that the remaining
polymer structure remains disposed on the external surface of the
substrate after the substructure has been selectively removed.

3. The method of claim 2, wherein said reducing the aspect ratio is
performed before said selectively removing one polymer structure is
performed and before said selectively removing the substructure is
performed, and wherein either: i) said selectively removing the
substructure is performed before said selectively removing one polymer
structure is performed or ii) said selectively removing one polymer
structure is performed before said selectively removing the substructure
is performed.

4. The method of claim 2, wherein said reducing the aspect ratio is
performed after said selectively removing the substructure is performed
and before said removing one polymer structure is performed.

5. The method of claim 2, wherein said selectively removing the
substructure is performed before said reducing the aspect ratio is
performed and before said removing one polymer structure is performed,
and wherein said reducing the aspect ratio and said removing one polymer
structure are performed simultaneously.

6. The method of claim 1, wherein the selectively removed one polymer
structure is the first polymer structure and the remaining polymer
structure is the second polymer structure, and wherein the method further
comprises: selectively removing the substructure such that the remaining
polymer structure remains disposed on the external surface of the
substrate after the substructure has been selectively removed.

7. The method of claim 6, wherein said reducing the aspect ratio is
performed before said selectively removing one polymer structure is
performed and before said selectively removing the substructure is
performed, and wherein either: i) said selectively removing the
substructure is performed before said selectively removing one polymer
structure is performed or ii) said selectively removing one polymer
structure is performed before said selectively removing the substructure
is performed.

8. The method of claim 6, wherein said reducing the aspect ratio is
performed after said selectively removing the substructure is performed
and before said removing one polymer structure is performed.

9. The method of claim 6, wherein said selectively removing the
substructure is performed before said reducing the aspect ratio is
performed and before said removing one polymer structure is performed,
and wherein said reducing the aspect ratio and said removing one polymer
structure are performed simultaneously.

10. The method of claim 1, wherein the selectively removed one polymer
structure is the second polymer structure and the remaining polymer
structure is the first polymer structure, and wherein the substructure
remains disposed on the external surface of the substrate after the one
polymer structure has been selectively removed.

11. The method of claim 10, wherein said reducing the aspect ratio is
performed before said selectively removing one polymer structure is
performed.

12. The method of claim 10, wherein said reducing the aspect ratio and
said removing one polymer structure are performed simultaneously.

13. The method of claim 1, wherein the selectively removed one polymer
structure is the first polymer structure and the remaining polymer
structure is the second polymer structure, and wherein the substructure
remains disposed on the external surface of the substrate after the one
polymer structure has been selectively removed.

14. The method of claim 13, wherein said reducing the aspect ratio is
performed before said selectively removing one polymer structure is
performed.

15. The method of claim 13, wherein said reducing the aspect ratio and
said removing one polymer structure are performed simultaneously.

16. The method of claim 1, wherein said at least one polymer structure is
the first polymer structure or the second polymer structure.

17. The method of claim 1, wherein said at least one polymer structure is
the first polymer structure and the second polymer structure.

19. The method of claim 1, wherein the first polymer or the second
polymer is a silicon-containing polymer having a same structure as is
obtained via hydrolysis and condensation of at least one hydrolyzable
silane compound selected from the group consisting of a hydrolyzable
silane compound shown by formula (1), a hydrolyzable silane compound
shown by formula (2), and a hydrolyzable silane compound shown by formula
(3): RaSi(OR1)4-a (1) wherein R represents a fluorine
atom, a linear or branched alkyl group having 1 to 5 carbon atoms, an
alkenyl group having 2 to 6 carbon atoms, or an alkylcarbonyloxy group,
wherein R1 represents a monovalent organic group, and wherein a
represents an integer from 1 to 3; Si(OR2)4 (2) wherein
R2 represents a monovalent organic group;
R3x(R4O)3-xSi--(R7)z-Si(OR5)3-yR6y
(3) wherein R3 and R6 independently represent a fluorine atom,
an alkylcarbonyloxy group, or a linear or branched alkyl group having 1
to 5 carbon atoms, wherein R4 and R5 independently represent a
monovalent organic group, wherein x and y independently represent a
number from 0 to 2, wherein R7 represents an oxygen atom, a
phenylene group, or a group --(CH2)m--, wherein m represents an
integer from 1 to 6, and wherein z represents 0 or 1.

20. The method of claim 1 wherein said substructure comprises a
photoresist.

21. The method of claim 1, further comprising transferring a pattern
comprising the remaining polymer structure into the substrate.

22. The method of claim 1, wherein said forming the structural
configuration comprises: applying a solution comprising the first polymer
and the second polymer to the substructure, said sidewall comprising a
first material, a selective chemical affinity of the first polymer for
the first material being greater than a selective chemical affinity of
the second polymer for the first material; and segregating the first
polymer from the second polymer, said first polymer selectively
segregating to the sidewall resulting in the first polymer being disposed
between the sidewall and the second polymer to form the structural
configuration.

Description:

FIELD OF THE INVENTION

[0001] The invention relates to a method for improving self-assembled
polymer features.

BACKGROUND OF THE INVENTION

[0002] Smaller critical dimension (CD) allows denser circuitry to be
created and therefore reduces the overall production cost of
microelectronic devices. However, there exists a need for a high
throughput method to cost effectively pattern features with dimensions or
pitches smaller than those which can be fabricated by optical
lithography. Self-segregating polymer blends provide a route to generate
self-assembled polymer features next to existing topographical features
on a wafer. However, such self-assembled polymer features may become
distorted or even collapse during their formation or further processing
of the resultant polymer pattern. Thus, there is a need to improve the
self-assembled polymer features resulting from self-segregated polymer
blends in order to retain pattern fidelity.

SUMMARY OF THE INVENTION

[0003] The present invention provides a method for processing structures,
said method comprising:

[0004] forming a structural configuration, said structural configuration
comprising a substrate, a substructure having a sidewall and disposed on
an external surface of the substrate, a first polymer structure disposed
on the external surface of the substrate and in direct mechanical contact
with the sidewall, and a second polymer structure disposed on the
external surface of the substrate and in direct mechanical contact with
the first polymer structure such that the first polymer structure is
disposed between the sidewall and the second polymer structure, said
first polymer structure comprising a first polymer, said second polymer
structure comprising a second polymer;

[0005] reducing an aspect ratio of each polymer structure of at least one
polymer structure with respect to the external surface of the substrate,
said reducing comprising removing an upper portion furthest from the
substrate of each polymer structure of the at least one polymer
structure, said at least one polymer structure selected from the group
consisting of the first polymer structure, the second polymer structure,
and both the first polymer structure and the second polymer structure;
and

[0006] selectively removing one polymer structure from the structural
configuration such that a remaining polymer structure remains disposed on
the external surface of the substrate after the one polymer structure has
been selectively removed, said reducing having reduced the aspect ratio
of the remaining polymer structure, wherein either the selectively
removed one polymer structure is the first polymer structure and the
remaining polymer structure is the second polymer structure or the
selectively removed one polymer structure is the second polymer structure
and the remaining polymer structure is the first polymer structure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1A is an illustration of a substrate with a substructure
disposed on a surface of the substrate, in accordance with embodiments of
the present invention.

[0008] FIG. 1B is an illustration of the substrate and substructure of
FIG. 1A after applying a solution to the substructure, in accordance with
embodiments of the present invention.

[0009] FIG. 1C is an illustration of the solution in FIG. 1B after
segregating the first polymer from the second polymer, in accordance with
embodiments of the present invention.

[0010] FIG. 1D is an illustration of FIG. 1C after selectively removing
the second polymer structures, in accordance with embodiments of the
present invention.

[0011] FIG. 1E is an illustration of FIG. 1C, where the substructures have
been removed, in accordance with embodiments of the present invention.

[0012] FIG. 1F is an illustration of FIG. 1E, where the second polymer
structures have been removed, in accordance with embodiments of the
present invention.

[0013] FIG. 1G is an illustration of FIG. 1F after transferring the
pattern of first polymer structures to the substrate, in accordance with
embodiments of the present invention.

[0014] FIG. 1H is an illustration of FIG. 1G after removal of the first
polymer structures, in accordance with embodiments of the present
invention.

[0015] FIG. 2A is an illustration of the example of FIG. 1B after
segregating the first polymer from the second polymer to form polymer
structures, in accordance with embodiments of the present invention.

[0016]FIG. 2B is an illustration of example of FIG. 2A after removing a
second portion of said structure comprising the first polymer, in
accordance with embodiments of the present invention.

[0017]FIG. 3 is a flow chart illustrating a material alignment method, in
accordance with embodiments of the present invention.

[0018]FIG. 4A depicts processes in which self assembled polymer
structures are formed on a substrate, in accordance with embodiments of
the present invention.

[0019] FIG. 4B depicts the substrate of FIG. 4A and a polymer structure
disposed on an exterior surface of the substrate, in accordance with
embodiments of the present invention.

[0020] FIGS. 5A-5B illustrate collapse of the polymer spacer pattern of
FIG. 4A, in accordance with embodiments of the present invention.

[0021] FIGS. 6A-6D depict a reference process and three slimming processes
for generating final structures, in accordance with embodiments of the
present invention

[0022] FIGS. 7A-7D depict final structures resulting from a reference
process and from three slimming processes which remove a substructure and
decrease the aspect ratio of a second polymer structure such that the
first polymer structure is disposed between the second polymer structure
and a sidewall of the substructure, in accordance with embodiments of the
present invention.

[0023] FIGS. 8A-8D depict final structures resulting from a reference
process and from three slimming processes which do not remove
substructure and decrease the aspect ratio of a first polymer structure
disposed between a second polymer structure and a sidewall of the
substructure, in accordance with embodiments of the present invention.

[0024] FIGS. 9A-9D depict final structures resulting from a reference
process and from three slimming processes which do not remove a
substructure and decrease the aspect ratio of a second polymer structure
such that the first polymer structure is disposed between the second
polymer structure and a sidewall of the substructure, in accordance with
embodiments of the present invention.

[0025] FIG. 10A shows the "slimming first" scheme of FIG. 6B, in
accordance with embodiments of the present invention.

[0026] FIG. 10B is the cross-section SEM images of the AcOMBS lines formed
using the reference process shown in FIG. 6A, in accordance with
embodiments of the present invention.

[0027] FIGS. 10C to 10G are the cross-section SEM images of the final
AcOMBS lines formed using the "slimming first" scheme in FIG. 10A, in
accordance with embodiments of the present invention.

[0028] FIG. 11A shows the "slimming between" scheme of FIG. 6C, in
accordance with embodiments of the present invention.

[0029] FIGS. 11B and 11E shows cross-section SEM images of 100K and 20K
magnification, respectively, of the AcOMBS lines formed using the
reference process shown in FIG. 6A (i.e., without slimming), in
accordance with embodiments of the present invention. Some AcOMBS lines
collapse and other AcOMBS lines do not form perpendicular to the
substrate and bend toward the space which was occupied by the
substructure.

[0030]FIG. 11C and FIG. 11F shows cross-section SEM images of 100K and
20K magnification, respectively, of the AcOMBS lines for the "slimming
between" scheme of FIG. 11A using IPA as a slimming solvent, in
accordance with embodiments of the present invention.

[0031] FIG. 11D and FIG. 11G shows cross-section SEM images of 100K and
20K magnification, respectively, of the AcOMBS lines for the "slimming
between" scheme of FIG. 11A using a mixture solvent of MeOH:H2O=80:20, in
accordance with embodiments of the present invention.

[0032] FIG. 12A shows the "slimming together" scheme of FIG. 6D, in
accordance with embodiments of the present invention.

[0033] FIG. 12B shows cross-section SEM images of AcOMBS lines formed
using the reference process shown in FIG. 6A (i.e., without slimming), in
accordance with embodiments of the present invention.

[0034] FIG. 12C shows cross-section SEM images of AcOMBS lines after
selective removal of the substructure followed by a slimming/developing
step of FIG. 12A using a mixture solvent of cyclohexane:acetone=96:4
(wt/wt), in accordance with embodiments of the present invention.

[0035] FIG. 12D shows cross-section SEM images of AcOMBS lines after
selective removal of the substructure followed by a slimming/developing
step of FIG. 12A using a mixture solvent of cyclohexane:acetone=98:2
(wt/wt), in accordance with embodiments of the present invention.

[0036] FIG. 13 is a flow chart describing a method for processing a
structure, in accordance with embodiments of the present invention.

[0037] FIG. 14 is a flow chart describing a method for implementing the
step of forming the structure in FIG. 13, in accordance with embodiments
of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0038] Although certain embodiments of the present invention will be shown
and described in detail, it should be understood that various changes and
modifications may be made without departing from the scope of the
appended claims. The scope of the present invention will in no way be
limited to the number of constituting components, the materials thereof,
the shapes thereof, the relative arrangement thereof, etc., and are
disclosed simply as examples of embodiments. The features and advantages
of the present invention are illustrated in detail in the accompanying
drawings, wherein like reference numerals refer to like elements
throughout the drawings. Although the drawings are intended to illustrate
the present invention, the drawings are not necessarily drawn to scale.

[0039] The detailed description of the present invention is organized into
the following sections:

[0040] 1. Aligning Polymer Films and Related Structures;

[0041] 2. Improving Self-Assembled Polymer Features

1. Aligning Polymer Films and Related Structures

[0042] The following are definitions:

[0043] A monomer as used herein is a molecule that can undergo
polymerization which contributes constitutional units to the essential
structure of a macromolecule, an oligomer, a block, a chain, and the
like.

[0044] A polymer as used herein is a macromolecule comprising multiple
repeating smaller units or molecules (monomers) derived, actually or
conceptually, from smaller units or molecules, bonded together covalently
or otherwise. The polymer may be natural or synthetic.

[0045] A copolymer as used herein is a polymer derived from more than one
species of monomer.

[0046] A block copolymer as used herein is a copolymer that comprises more
than one species of monomer, wherein the monomers are present in blocks.
Each block of the monomer comprises repeating sequences of the monomer. A
formula (1) representative of a block copolymer is shown below:

-(A)a-(B)b-(C)c-(D)d- (1)

wherein A, B, C, and D represent monomer units and the subscripts "a",
"b", "c", and "d", represent the number of repeating units of A, B, C,
and D respectively. The above referenced representative formula is not
meant to limit the structure of the block copolymer used in an embodiment
of the present invention. The aforementioned monomers of the copolymer
may be used individually and in combinations thereof in accordance with
the method of the present invention.

[0047] A di-block copolymer has blocks of two different polymers. A
formula (2) representative of a di-block copolymer is shown below:

-(A)m-(B)n- (2)

where subscripts "m" and "n" represent the number of repeating units of A
and B, respectively. The notation for a di-block copolymer may be
abbreviated as A-b-B, where A represents the polymer of the first block,
B represents the polymer of the second block, and -b- denotes that it is
a di-block copolymer of blocks of A and B. For example, PS-b-PMMA
represents a di-block copolymer of polystyrene (PS) and
polymethylmethacrylate (PMMA).

[0048] A substrate, as used herein, is a physical body (e.g., a layer or a
laminate, a material, and the like) onto which materials (such as
polymers, polymeric materials, metals, oxides, dielectrics, etc.) may be
deposited or adhered.

[0049] A nanoparticle as used herein is a particle on the order of 1
nanometer (nm) to 100 nm in dimension. Examples of the structure may
include but are not limited to nanorods, nanosheets, nanospheres,
nanocylinders, nanocubes, nanoparticles, nanograins, nanofilaments,
nanolamellae, and the like having solid composition and a minimal
structural dimension in a range from about 1 nm to about 100 nm.

[0050] The substrates described herein may include semiconducting
materials, insulating materials, conductive materials, or any combination
thereof, including multilayered structures. Thus, for example, a
substrate may comprise a semiconducting material such as Si, SiGe, SiGeC,
SiC, GaAs, InAs, InP and other III/V or II/VI compound semiconductors. A
substrate may comprise, for example, a silicon wafer or process wafer
such as that produced in various steps of a semiconductor manufacturing
process, such as an integrated semiconductor wafer. A substrate may
comprise a layered substrate such as, for example, Si/SiGe, Si/SiC,
silicon-on-insulators (SOIs) or silicon germanium-on-insulators (SGOIs).
A substrate may comprise layers such as a dielectric layer, a barrier
layer for copper such as SiC, a metal layer such as copper, a hafnium
dioxide layer, a silicon layer, a silicon oxide layer, the like, or
combinations thereof. A substrate may comprise an insulating material
such as an organic insulator, an inorganic insulator or a combination
thereof including multilayers. In particular, a substrate may comprise an
organic insulating material such as an amorphous carbon-rich material
formed via a spin-on or chemical vapor deposition process. A substrate
may comprise an organic or inorganic anti-reflection coating. In
particular, the anti-reflection coating may be comprised of organic
polymers, inorganic polymers (e.g., silicon containing), or inorganic
materials (e.g., silicon nitride). A substrate may comprise a conductive
material, for example, polycrystalline silicon (polySi), an elemental
metal, alloys of elemental metals, a metal silicide, a metal nitride, or
combinations thereof, including multilayers. A substrate may comprise ion
implanted areas, such as ion implanted source/drain areas having P-type
or N-type diffusions active to the surface of the substrate.

[0051] In some embodiments, a substrate may include a combination of a
semiconducting material and an insulating material, a combination of a
semiconducting material and a conductive material or a combination of a
semiconducting material, an insulating material and a conductive
material. An example of a substrate that includes a combination of the
above is an interconnect structure.

[0052] FIG. 1A is an illustration of a substrate 101 with a substructure
105 disposed on a surface of the substrate 101. The substructure 105 may
comprise at least one feature 102, having at least one sidewall 115 and
an adjoining bottom 120. The at least one feature 102 may comprise a
plurality of features, for example. The bottom 120 may be essentially
perpendicular to the sidewall 115. The bottom 120 may be defined by an
exposed portion of the surface of the substrate 101. The bottom 120 may
comprise a material which is the same or different from material
comprising the at least one sidewall 115. The structures herein, in
addition to at least one sidewall and a bottom, may comprise, for
example, holes, trenches, vias, posts, lines, or a combination of these.
The at least one sidewall 115 may comprise two sidewalls 115 separated by
a distance 117. The substructure 105 may comprise the summation of all
the material in a layer comprising the topography and may be continuous
or non-continuous as necessary to form patterns that include holes,
posts, islands, lines, and trenches, etc., any of which may be isolated
or nested.

[0053] The substructure 105 may be integral with the substrate 101, for
example, the substrate 101 surface may comprise a plurality of holes
etched into a substrate surface by a method such as by reactive ion
etching (RIE). The substructure 105 may be formed on the substrate
surface by a process such as patterning a photoresist, patterning a
polymer, patterning an inorganic material, etching, chemical vapor
deposition, sputtering, atomic layer deposition, coating, chemical
attachment, or a combinations of these. Chemical attachment may comprise
the use of chemical shrink materials to deposit layers onto the
substrate.

[0054] FIG. 1B is an illustration of the substrate 101 and substructure
105 of FIG. 1A after applying a solution 300 to the substructure 105. The
solution 300 may comprise two or more immiscible polymers, where the two
or more immiscible polymers may comprise a first polymer and a second
polymer. The first polymer may have a chemical affinity for the material
of the sidewalls 115 which is higher than the chemical affinity of the
second polymer for the sidewalls 115. Applying the solution may for a
film having a thickness in a range from about 5 nanometers (nm) to about
500 nm.

[0055] Additional materials (such as a RELACS®-type material) may be
used to modify the substructure, where additional layers may be deposited
onto the sidewalls to adjust the chemical properties of the sidewall such
that they will have an increased or decreased affinity for the two or
more immiscible polymers. For example, a polar chemical shrink material
may be used to increase the polarity of the sidewalls to favor
interactions with the more polar component of the two or more immiscible
polymers. Also, a more hydrophobic shrink material may be deposited on
the sidewalls to favor interactions with a non-polar component of the two
or more polymers. In addition, shrink materials having functional groups
may be deposited on the sidewalls to promote affinity for polymer that
will have specific interactions with them (i.e., ionic bonds, hydrogen
bonding, etc.) in order to control which of the two or more polymers will
sequester next to the at least one sidewall.

[0056] The term "immiscible" as used herein refers to the at least two
polymers in the polymer blend being incompatible enough to drive phase
segregation under certain process conditions. The immiscibility of the
polymers in the polymer blends may depend on the composition as well as
the film forming process of the polymer blends. The ratio of the
polymers, molecular weight of the individual polymers in the blend, and
the presence of other additional components in the blend may adjust the
compatibility of the polymers in the polymer blend. Temperature, coating
conditions, and substrate surface properties may also affect the
segregation of the polymers in the substrate topography. As used herein,
an "immiscible polymer" is defined as a polymer from a polymer blend
composition which segregates in the topography on a properly prepared
topographical substrate under proper process conditions.

[0058] The solution 300 comprising the first and second polymers may
further comprise a third polymer. Examples of a third polymer include,
homopolymers, block copolymers, graft copolymers, and random copolymers
For example, if a polymer blend is made from immiscible polymer A and
immiscible polymer B, then a A-b-B, A-grafted-B, or A-ran-B can be used
to adjust the interfacial energy between domains of polymer A and domains
of polymer B, where A-grafted-B denotes a grafted copolymer of polymer A
and polymer B, and A-ran-B denotes a random block copolymer of polymer A
and polymer B. For example, adding A-b-B or A-grafted-B would reduce the
interfacial energy between polymer A and polymer B, and, therefore,
affect the segregation behavior of the polymer blends. In addition, the
lateral dimension of the polymer domains formed after segregation may
depend on the ratio of polymer A and polymer B and the additional
components in the blend.

[0059] The solution 300 may comprise one or more additional components,
such as photosensitive acid generators, surfactants, base quenchers,
nanoparticles, metal compounds, inorganic compounds, and solvents. The
nanoparticles may comprise materials such as inorganic oxides (alumina,
titania, halfnia, etc.), inorganic nitrides, inorganic carbide, or metals
(gold, etc.). Examples of inorganic compounds include organometallic
compounds, such as ferrocene, which may impart high oxygen etch
resistance to the polymer domain in which the metal compound are
dissolved. Examples of inorganic compounds include organosilicates or
organosilicon/organogermanium compounds, which may readily form etch
resistant glasses during oxygen reactive ion etching (RIE) processes.

[0060] Surfactants described herein may be used to improve coating
uniformity, and may include ionic, non-ionic, monomeric, oligomeric, and
polymeric species, or combinations thereof. Examples of possible
surfactants include fluorine-containing surfactants such as the
FLUORAD® series available from 3M Company in St. Paul, Minn., and
siloxane-containing surfactants such as the SILWET® series available
from Union Carbide Corporation in Danbury, Conn.

[0061] Solvents described herein may be used to dissolve the components in
the solution 300, so that the solution 300 may be applied evenly on the
substrate surface to provide a defect-free coating. Some examples of
suitable solvents include ethers, glycol ethers, aromatic hydrocarbons,
ketones, esters, ethyl lactate, gamma-butyrolactone (GBL), cyclohexanone,
ethoxyethylpropionate (EEP), a combination of EEP and GBL, and propylene
glycol methyl ether acetate (PGMEA). The embodiments described herein are
not limited to the selection of any particular solvent. The solvent for
the solution 300 may be chosen such that the solvent does not dissolve
the substructure or underlying layers of the substrate.

[0062] Base quenchers described herein may comprise aliphatic amines,
aromatic amines, carboxylates, hydroxides, or combinations thereof. For
example, base quenchers may include: tetra alkyl ammonium hydroxides,
cetyltrimethyl ammonium hydroxide, dimethylamino pyridine,
7-diethylamino-4-methyl coumarin (Coumarin 1), tertiary amines,
sterically hindered diamine and guanidine bases such as
1,8-bis(dimethylamino)naphthalene (PROTON SPONGE), berberine, or
polymeric amines such as in the PLURONIC® or TETRONIC® series
commercially available from BASF. The embodiments described herein are
not limited to any specific selection of these expedients.

[0063] The photosensitive acid generators (PAG) described herein are
capable of producing or generating an amount of acid (such as 1 mole of
acid per mole of PAG, for example) upon exposure to a dose of
electromagnetic radiation, such as visible, ultraviolet (UV) and extreme
ultraviolet (EUV), for example. The PAG may comprise, for example,
triphenyl sulfonium nonaflate (TPSN),
(trifluoro-methylsulfonyloxy)-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide
(MDT), N-hydroxy-naphthalimide dodecane sulfonate (DDSN), onium salts,
aromatic diazonium salts, sulfonium salts, diaryliodonium salts, sulfonic
acid esters of N-hydroxyamides, imides, or combinations thereof.

[0064] The solution 300 may be applied by spin coating the solution 300
onto the substrate 101 at a spin speed in a range from about 1 rpm to
about 10,000 rpm. The solution 300 may be spin coated at room temperature
without a post-drying process. The applied solution 300 may be thermally
annealed, for example, at a temperature above the glass transition
temperature of the first polymer and above the glass transition
temperature of the second polymer. The applied solution 300 may be vapor
annealed, after applying the solution 300 to the substrate 101, such as
by annealing the applied solution 300 under organic solvent vapor at or
above room temperature (about 25° C.) from about 10 hours to about
15 hours, for example.

[0065] The spin coating process used is not meant to limit the type of
processes that may be used when applying the solution to the substructure
105. Other processes such as dip-coating and spray-coating, a combination
thereof, or any other process which provides a means for applying the
solution 300 to the substructure 105 may be employed.

[0066] FIG. 1C is an illustration of the solution in FIG. 1B after
segregating the first polymer 400 from the second polymer 405. The first
polymer 400 selectively migrates to the at least one sidewall 115 of the
at least one feature 102, resulting in the first polymer 400 being
disposed between the sidewall 115 and the second polymer 405. The second
polymer 405 may be disposed in a central position between sidewalls of
two adjacent portions of the substructure 105, and separated from each
sidewall 115 by a layer of the first polymer 400. The first polymer 400
may migrate towards the at least one sidewall 115 due to having a higher
affinity for the at least one sidewall 115 than does the second polymer
405. The second polymer 405 may be excluded from the at least one
sidewall 115 by the first polymer 400 due to the lower affinity of the
second polymer 405 for the at least one sidewall 115. For example, the at
least one sidewall may comprise a hydrophilic material and the first
polymer may comprise a hydrophilic polymer, where the second polymer may
comprise a hydrophobic polymer. In such a case, the first polymer would
have a much stronger selective chemical affinity for the at least one
sidewall than would the second polymer. In the example illustrated in
FIG. 1C, neither the first polymer 400 nor the second polymer 405 have a
higher selective chemical affinity for the material comprising the bottom
120 of the feature 102. Thus in FIG. 1C, the first polymer 400 and the
second polymer 405 are distributed in a polymer segregation pattern in
which the first polymer 400 and the second polymer 405 are distributed in
a direction 10 or 11 that is perpendicular to each sidewall of the at
least one sidewall 115.

[0067] FIG. 1D is an illustration of FIG. 1C after selectively removing
the structures comprising the second polymer 405, resulting in forming
structures on the substrate 101, where the structures comprise the
substructure 105 and the first polymer 400 remaining on the surface.

[0068] Selective removal of substructure 105, the structure comprising
first polymer 400, or the structure comprising second polymer 405 may
comprise using a process such as developing (such as developing in
aqueous base developer), dissolving in solvent, and plasma etching, where
the selected process may selectively remove the targeted structures and
leave others remaining. In the example of FIG. 1D, the second polymer 405
of FIG. 1C has been selectively removed, resulting in forming structures
comprising the first polymer 400 and the substructure 105 on the
substrate 101, and resulting in the first immiscible polymer remaining
against the at least one sidewall 115 and reducing an effective dimension
of the feature (e.g., distance 117--see FIG. 1A). A dimension of the
feature may comprise the lateral width (such as a spacing between two or
more sidewalls), diameter (such as in a case where the feature is a
cylindrical hole), the depth of a hole, or a combination of these. Where
polymer remains disposed against a sidewall 115, for example, the
effective distance 117 between the sidewalls has been reduced by the
thicknesses of the polymer layers formed. Where the feature comprises a
hole, the effective diameter of the hole may be reduced in a similar
manner.

[0069] FIG. 1E is an illustration of FIG. 1C, where the substructure 105
has been removed. Removal of the substructure 105 results in forming
structures comprising a pattern of spaces 410, and subfeatures, where the
subfeatures include structures that comprise the first polymer 400 and
the second polymer 405 remaining on the surface.

[0070] FIG. 1F is an illustration of FIG. 1E, where the structures
comprising the second polymer 405 have been removed, resulting in
structures remaining on the substrate, where the remaining structures
comprise the first polymer 400. Alternatively, FIG. 1F can be considered
to be an illustration of FIG. 1D, where the substructure 105 has been
removed, resulting in structures remaining on the substrate, where the
structures comprise the first polymer 400.

[0071] FIG. 1G is an illustration of FIG. 1F after transferring the
pattern of the structures comprising the first polymer 400 to the
substrate 101. FIG. 1H is an illustration of FIG. 1G after removal of the
structures comprising the first polymer 400 to leave the patterned
substrate 101 remaining.

[0072] FIG. 2A is an illustration of the example of FIG. 1B after
segregating the first polymer 400 from the second polymer 405, where the
first polymer 400 has a higher affinity for the material comprising the
bottom 120 than does the second polymer 405, resulting in a first portion
500 of said first polymer 400 being disposed between the second polymer
405 and the bottom 120. In FIG. 2A, the bottom material may comprise the
same material as the at least one sidewall or may comprise a material
which is sufficiently chemically similar such that the first polymer has
a higher affinity for the bottom than does the second polymer. For
example, the at least one sidewall and the bottom may each comprise
hydrophobic materials, where the first polymer comprises a hydrophobic
polymer and the second polymer comprises a hydrophilic polymer.

[0073]FIG. 2B is an illustration of an example of FIG. 2A after removing
a second portion of said first polymer 400, resulting in a structure
remaining on the surface of the substrate, where the structure comprises
the substructure 105, the second polymer 405, and the first portion 500
of the first polymer 400 disposed between the second polymer 405 and the
bottom 120. Removing selectively the first polymer 400 results in
formation of spaces 505 between the at least one sidewall 115 and the
second polymer 405 remaining.

[0074]FIG. 3 is a flow chart illustrating a method. Step 300 comprises
forming a composition comprising two or more immiscible polymers. The two
or more immiscible polymers may comprise a first immiscible polymer and a
second immiscible polymer, such as those described above. The composition
may comprise a third material blended with the two or more immiscible
polymers. The third material may be miscible with the first polymer, the
second polymer, both the first polymer and the second polymer, or neither
the first polymer nor the second polymer. The third material may comprise
a polymer having a structure where a first portion of the structure is
miscible with the first polymer and a second portion of the structure is
miscible with the second polymer. For example, the third material may
comprise a block copolymer having polymer blocks miscible with the first
polymer, polymer blocks miscible with the second polymer, or a
combination of these.

[0075] Step 305 comprises forming a film of the composition on a
topographically patterned surface of a substrate, where the surface may
have a plurality of features disposed thereon, such as the substrates
described above having substructures disposed thereon. Each feature of
the plurality of features may have at least one sidewall essentially
perpendicular to the surface, such as a trench having at least two
sidewalls, or a hole having one sidewall, for example. Each feature may
be separated from adjacent features by a distance across the substrate
surface. Examples of features include holes, posts, islands, lines, and
trenches, etc., any of which may be isolated or nested. The at least one
sidewall may comprise a first material, where said first immiscible
polymer has a selective chemical affinity for the first material which is
greater than the selective chemical affinity of the second immiscible
polymer for the first material. Step 305 may be implemented in various
embodiments such as embodiments discussed supra in conjunction with FIG.
1C.

[0076] Step 310 comprises segregating selectively the first immiscible
polymer to the at least one sidewall. The segregating of step 310 may
occur either during or after the film forming of step 305. The
segregating of the first polymer at the at least one sidewall may result
in excluding the second polymer from the at least one sidewall by the
first polymer due to the high affinity of the first polymer for the
material of the sidewall. As the first polymer forms a structure (e.g., a
layer or domain) next to the at least one sidewall, the second polymer
may be displaced away from the at least one sidewall by the first
polymer. This results in the first immiscible polymer forming a first
structure conforming to the at least one sidewall, and the second
immiscible polymer forming a second structure conforming to the first
layer. The first structure may be disposed between the at least one
sidewall and the second layer, resulting in the first structure, the
second structure and the third material aligning essentially parallel to
the at least one sidewall. As the first structure conforms to the at
least one side wall, the structure aligns with the at least one sidewall,
following the direction of the sidewall. For example, where the sidewall
is a sidewall of a hole, the first structure conforms to the sidewall and
aligns with and follows the circumference of the sidewall. Likewise, the
second layer aligns with and conforms to the direction of the first
structure.

[0077] A third material dissolved in the first structure or the second
structure may be automatically aligned with the structure in which it is
dissolved as the structure is formed and aligned. For a third material
such as a block copolymer, for example, in which a first portion of its
structure (e.g., a first polymer block) is miscible with the first
polymer and a second portion of its structure (e.g., a second polymer
block) is miscible with the second polymer, the third material may be
disposed along the interface between the first structure and the second
structure, where each portion of the third material's structure is
dissolved in the corresponding structure with which it is miscible. The
third material may be used to adjust the interfacial energy between first
and second polymers and thus optimize segregation of the first and second
polymer in the topography. The third material may be disposed at the
bottom surface if it has a higher chemical affinity for the bottom
surface than both of the immiscible polymers. If the third material has a
lower surface energy than the two immiscible polymers, it may be disposed
at the air interface of the resulting film. After forming the film, one
or more of the two or more immiscible polymers or the third material may
be removed from the film, as described for the polymers above.

[0078] The method of FIG. 3 may further comprise annealing the film either
after forming the film in step 300 or during forming the film in step
300. Annealing may comprise methods such as thermal annealing, solvent
vapor annealing, zone annealing, and combinations thereof. Annealing may
accelerate or otherwise induce the segregation of the two or more
polymers.

[0079] These embodiments described herein have a number of advantages over
conventional processes. For cases where it is desired to shrink the CD of
patterned spaces, conventional processes such as thermal reflow,
RELACS®, or SAFIER® have detrimental dependencies on pattern
geometry (density and pitch), process conditions (baking time and
temperature) and/or resist chemistry which limits that the process window
of these approaches. The embodiments disclosed herein provide a way to
reduce feature dimensions and are less sensitive to the resist chemistry
and process conditions. The lateral dimension of the segregated polymer
structures may be determined by the ratio of the different polymers used
in the composition. Since this ratio is predetermined, the resulting
dimensions of the segregated polymer structures may have less dependence
on bake temperature and bake time variations or specific resist
chemistry.

[0080] Processes employing double patterning and sidewall image transfer
techniques (e.g., self-aligned double patterning and spacer-based double
patterning techniques), when used to create patterns with dimensions
and/or pitches smaller than that of an initial pattern produced by
optical lithography, are very costly and process intensive. Often, they
require multiple patterning, deposition, or etch steps. The polymer blend
approach disclosed herein involves primarily spin-casting and baking
steps which can be performed by a single track tool. This track-only
process would advantageously lower process costs and increase throughput.

[0081] The immiscible polymers used in the segregating composition may be
selected appropriately for the respective process (i.e., shrink or
frequency multiplication). For example, for the process shown in FIG. 1D,
the first polymer may have higher affinity for the sidewall than the
second polymer. In addition, it is advantageous if the second polymer has
a higher etch rate or dissolution rate in developer than the first
polymer so that the second polymer can be selectively removed. This may
be accomplished, for example, by selecting a second polymer with a high
etch rate or dissolution rate in developer or by selecting a first
polymer with a lower etch rate or lower dissolution rate in developer.
The relative properties of either the first or second polymers may be
tuned by incorporating a third material that will co-assemble with one of
the polymers. For example, a organosilicate material can be added which
would co-assemble with a polymer such as poly(ethylene oxide) and
dramatically increase its oxygen plasma etch resistance.

[0082] For the method illustrated in FIG. 1E, it is advantageous where the
properties of the first and second polymers are such that the second
polymer can be easily removed by etching or dissolution in a developer.
For the method illustrated in FIG. 1F, the first polymer has a much
higher etch resistance than either the second polymer or the material
that comprises the substructure 105 (resist, transfer layer, hardmask,
etc.) in one embodiment. In one example where the substructure is a
photoresist (e.g., a patterned organic photoresist), it is advantageous
for the first polymer to contain elements such as silicon and germanium
that provide high oxygen etch resistance or if a third material (such as
an organosilicate) is co-assembled with the first polymer to provide such
high etch resistance.

[0083] Many equivalent techniques to engineer the desired properties into
the respective segregated polymer domains are known to those skilled in
the art and are included in the scope of this invention.

Example 1

[0084] A solution containing polystyrene (PS, 22 kilograms/more (kg/mole),
from polymer source) and polymethylmethacrylate (PMMA, 21 kg/mole from
polymer source) and polystyrene-block-polymethylmethacrylate (PS-b-PMMA,
38 kg/mole-36 kg/mole, from polymer source) with a PS:PMMA:PS-b-PMMA
weight ratio of 6:3:1 was cast onto a silicon wafer substrate coated with
an anti-reflective coating (ARC) with thermally hardened line/space
positive photoresist features having a pitch of 240 nm and then baked at
200° C. for 1 minute. PMMA segregated to form lines next to the
resist sidewall and PS segregated to the middle of the resist space.
PS-b-PMMA resided in the interface between PS and PMMA lines and was used
to tune the interfacial energy between PS and PMMA. The sample was etched
in an oxygen plasma for 10 seconds to remove the PMMA and showed
remaining PS and resist lines with pitch of 120 nm.

Example 2

[0085] A polymer blend solution containing polystyrene (PS, 22 kg/mole,
from polymer source) and polymethylmethacrylate (PMMA, 21 kg/mole from
polymer source) and polystyrene-block-polymethylmethacrylate (PS-b-PMMA,
38 kg/mole-36 kg/mole, from polymer source) with a PS:PMMA:PS-b-PMMA
weight ratio of 6:3:1 was cast on a substrate with negative e-beam resist
(XR1541, hydrogen silsesquioxane from Dow Corning, hydrophilic resist)
line/space features with a pitch of 110 nm and resist space from 50 nm to
80 nm. The sample was baked at 200° C. for 1 minute and etched
under oxygen plasma for 10 sec. The remaining PS and resist lines
demonstrated successful self-segregation in the narrower resist spaces.

Example 3

[0086] A polymer blend solution of poly (1-(4-hydroxyphenyl)ethyl
silsesquioxane-ran-(1-(phenyl)ethyl silsesquioxane))
(poly(HMBS50-r-MBS50) and
poly(1,1,1-trifluoro-2-(trifluoromethyl)-2-hydroxy-pent-4-yl
methacrylate) (poly(iPrHFAMA) with weight ratio 1:1 was cast on a
substrate with line/space and hole/post features of a standard 193 nm
positive resist (AR 1682). The sample was baked at 200° C. for 1
minute, developed in 0.26 N tetramethylammonium hydroxide solution (CD26
developer) for one minute, then rinsed and dried. The poly(iPrHFAMA) was
removed by CD26 developer, and poly(HMBS50-r-MBS50) was left
forming lines in between the resist lines and forming dots in between
resist dots.

2. Improving Self-Assembled Polymer Features

[0087] As described supra in conjunction with Section 1, self-assembled
polymer blends provide a route to generate polymer features next to the
existing topographical features. This portion of the detailed description
(Section 2) of the present invention describes a method and system for
improving polymer features on substrates such as, inter alia, the
self-assembled polymer features generated according to the methodology of
the previous portion (Section 1) of the detailed description of the
present invention.

[0089]FIG. 4A depicts processes in which self assembled polymer features
are formed, in accordance with embodiments of the present invention. As
shown in FIG. 4B, a solution of polymer blend of polymers A and B is cast
onto a substrate 11 with resist features comprising substructures S. The
polymer blend self-segregates between topographic features of
substructures S to form the structure 10 as shown in FIG. 4A. In the case
of a blend of two polymers A and B, both polymer A and polymer B flow
into trenches or holes between the sidewalls of substructure S. Substrate
11 of FIG. 4A is analogous to substrate 101 of FIG. 1B. Substructure S of
FIG. 4A is analogous to substructure 105 of FIG. 1C. The solution of the
polymer blend used (but not explicitly shown) in conjunction with FIG. 4A
is analogous to the solution 300 in FIG. 1B.

[0090] Since polymer A and polymer B have limited miscibility, this
polymer blend of polymer A and polymer B tends to self-segregate into a
polymer A region and a polymer B region where polymer A has higher
affinity to the substructure S sidewall than polymer B. Therefore,
polymer A preferentially segregates next to the sidewalls of substructure
S and polymer B preferentially segregates to a center region between the
substructures S. Polymers A and B of FIG. 4A are respectively analogous
to polymers 400 and 405 of FIG. 1C.

[0091] After segregation, one or more polymers may be selectively removed
from the segregated film (e.g., by alkaline developer, solvent, or
plasma) while leaving at least one polymer on the substrate 11, as
depicted in FIG. 4A. If polymer B is selectively removed, polymer A is
left with the original topography, the result of which is a reduction
(i.e., shrinking) of the lateral dimensions of the original topographical
openings. If polymer A is selectively removed, the structures comprising
polymer B along with the original topography of substructures S form a
pattern with a doubled frequency (i.e., half the original spatial
periodicity) relative to that of the original substructures S. If both
the original topography of substructures S and polymer B are selectively
removed, sidewall spacers of polymer A are formed on the substrates with
a doubled frequency (i.e., half the original spatial periodicity)
relative to that of the original substructures S.

[0092] FIG. 4B depicts the substrate 11 of FIG. 4A and a polymer structure
30 disposed on an exterior surface 15 of the substrate 11, in accordance
with embodiments of the present invention. The polymer structure 30
comprises the polymer A or polymer B of FIG. 4A and is characterized by a
height H and a width W. The height H of the polymer structure 30 is in
the direction 21 that is perpendicular to the exterior surface 15 of the
substrate 11. The width W of the polymer structure 30 is the average
(e.g., mean, median) dimension of the polymer structure 30 (in the
direction 22) in a plane that is perpendicular to the direction 21 and
(equivalently) is parallel to the surface 15 of the substrate 11. The
aspect ratio of the polymer structure 30 with respect to the surface 15
is defined as H/W.

[0093] For example, when the polymer structures and substrate form a
line-space pattern, the width W of the polymer structure 30 is the
average (e.g., mean, median) dimension of the polymer structure 30 in the
direction 22, which is perpendicular to the lines (that is, the width of
the lines rather than the length of the lines). For arbitrary patterns
for which there are two or more possible widths W in the plane
perpendicular to direction 21, the smallest width should be used in the
calculation of the aspect ratio.

[0094] The cross-sectional shape of polymer structure 30 in a
perpendicular plane that is perpendicular to the direction 21 may be
polygonal (e.g., rectangular, square pentagonal), circular, etc.

[0095] FIGS. 5A-5B illustrates collapse of the polymer spacer pattern of
FIG. 4A, in accordance with embodiments of the present invention. FIG. 5A
depicts an ideal situation in which the pattern does not collapse and a
non-ideal situation in which the pattern collapses during the second
selective removal step. FIG. 5B shows cross-section scanning electron
microscopy (SEM) image of collapsed patterns from a polymer blend. The
collapse of the pattern depicted in FIG. 5B results from the aspect
ratios of structures comprising polymer A in the pattern being too high
to maintain structural stability during the second selective removal
step.

[0096] Pattern collapse is a critical patterning defect caused by the
deformation of the pattered features due to the capillary forces
experienced during wet development processing. The maximum stress
imparted on the patterned features is mainly determined by the
interfacial tension of rinse solvent, the space width in between
patterns, and the aspect ratio of the patterned features. Of course,
pattern collapse also depends upon the pattern geometry, the mechanical
modulus of the patterned features, the adhesion of the patterned features
to the underlying substrate, and other factors. However, of the possible
methods to prevent pattern collapse, reducing the aspect ratio is the
easiest and most effective method to reduce the maximum stress and
thereby minimize pattern collapse. There are two ways to reduce aspect
ratio: reducing the vertical height or increasing lateral width; however,
only by reducing the vertical height of the features can high pattern
densities be maintained.

[0097] The present invention provides a method and system configured to
improve the profiles of polymer features, such as polymer features from
self-segregated polymer blends, by preventing or reducing collapse of the
polymer spacer pattern.

[0098] FIGS. 6A-6D depict a reference process (FIG. 6A) and three slimming
processes (FIGS. 6B-6D) for generating final structures 60-63, in
accordance with embodiments of the present invention. The step of
"slimming" a polymer structure means reducing the vertical aspect ratio
of the polymer structure with respect to the exterior surface of the
substrate that the polymer structure is disposed on. The reference
process of FIG. 6A generates the final structure 60 without slimming. The
three slimming processes of FIGS. 6B-6D remove the substructure S,
decrease the aspect ratio of a first polymer structure (comprising
polymer A) disposed between a second polymer structure (comprised of
polymer B) and a sidewall of the substructure S, and remove the second
polymer structure (comprising polymer B). The processes of FIGS. 6B-6D
prevent or reduce collapse of the polymer spacer pattern.

[0099] FIG. 6A depicts two selective removal (e.g., wet development,
plasma etch, etc.) steps in succession to selectively remove the
topography feature (substructure S) in the first selective removal step
and to selectively remove polymer B structures (comprising polymer B) in
the second selective removal step, which results in the polymer A spacer
pattern depicted the final structure 60. Unlike the processes of FIGS.
6B-6C, there is no slimming step in the process of FIG. 6A.

[0100] Although FIG. 6A depicts the selective removal of the topographic
substructures S being performed in the first selective removal step
before the selective removal of the polymer B structures is performed in
the second selective removal step, the selective removal of the polymer B
structures may alternatively be performed before the selective removal of
the topographic substructures S in one embodiment.

[0101] An alternative embodiment with respect to FIG. 6A is to selectively
remove the polymer A structures (instead of polymer B structures) in the
second selective removal step, which results in the polymer B spacer
pattern in the final structure 70 depicted in FIG. 7A (discussed infra)
instead of the polymer A spacer pattern in the final structure 60
depicted in FIG. 6A.

[0102] FIGS. 7A-7D depict final structures resulting from a reference
process (FIG. 7A) and from three slimming processes (FIGS. 7B-7D) which
remove the substructure S, decrease the aspect ratio of a second polymer
structure (comprising polymer B), and remove a first polymer structure
(comprising polymer A) that had been disposed between the second polymer
structure (comprising polymer B) and a sidewall of the substructure S, in
accordance with embodiments of the present invention. The processes of
FIGS. 7B-7D prevent or reduce collapse of the polymer spacer pattern.

[0103] In one embodiment, the first selective removal step of FIG. 6A is
not performed and the second selective removal step removes polymer B,
resulting in the topography feature (substructure S) remaining in the
final structure 80 depicted in FIG. 8A (discussed infra) which is
analogous to the Space Shrinkage structure in FIG. 4A.

[0104] FIGS. 8A-8D depict final structures 80-83, respectively, resulting
from a reference process (FIG. 8A) and from three slimming processes
(FIGS. 8B-8D) which do not remove the substructure S, decrease the aspect
ratio of a first polymer structure (comprising polymer A) disposed
between a second polymer structure (comprised of polymer B) and a
sidewall of the substructure S, and remove the second polymer structure
(comprising polymer B), in accordance with embodiments of the present
invention.

[0105] In one embodiment, the first selective removal step of FIG. 6A is
not performed and the second selective removal step removes polymer A
structures (as in the alternative embodiment of FIG. 7A described supra),
resulting in the topography feature (substructure S) remaining in the
final structure 90 depicted in FIG. 9A (discussed infra) which is
analogous to the Pattern Doubling structure in FIG. 4A.

[0106] FIGS. 9A-9D depict final structures 90-93, respectively, resulting
from a reference process (FIG. 9A) and from three slimming processes
(FIGS. 9B-9D) which do not remove the substructure S, decrease the aspect
ratio of a second polymer structure (comprising polymer B), and remove a
first polymer structure (comprising polymer A) that had been disposed
between the second polymer structure (comprising polymer B) and a
sidewall of the substructure S, in accordance with embodiments of the
present invention.

"Slimming First" Process

[0107] FIG. 6B depicts a "slimming first" process in which a slimming
solvent (or another removal process such as a plasma etch) is applied
before a first selective removal step to reduce the height of a polymer A
structure (in the direction 21) which reduces the aspect ratio of a
polymer A structure with respect to the exterior surface of the
substrate. The slimming step in FIG. 6B serves to reduce the height of a
polymer A structure in direction 21, resulting in a shorter polymer A
structure with a reduced aspect ratio. In one embodiment, the height of a
polymer B structure in direction 21 is also reduced in the slimming step
of FIG. 6B. In this case, shorter sidewall spacers form after slimming
and two selective removal steps (e.g., wet development steps) in
succession to selectively remove the topography feature (substructure S)
in the first selective removal step and then to selectively remove a
polymer B structure in the second selective removal step, which results
in the polymer A spacer pattern depicted the final structure 61 that has
shorter spacers than in the final structure 60 of FIG. 6A.

[0108] Although FIG. 6B depicts the selective removal of the polymer B
structures being performed in the second selective removal step after the
selective removal of the topographic substructures S is performed in the
first selective removal step, in one embodiment the selective removal of
the polymer B structures may instead be performed before the selective
removal of the topographic substructures S is performed.

[0109] An alternative embodiment with respect to FIG. 6B is to reduce the
height of a polymer B structure (or of both a polymer B and a polymer A
structure) in the slimming step and selectively remove a polymer A
structure (instead of a polymer B structure) in the second selective
removal step, which results in the polymer B spacer pattern in the final
structure 71 depicted in FIG. 7B instead of the polymer A spacer pattern
in the final structure 61 depicted in FIG. 6B. The final structure 71
depicted in FIG. 7B has shorter spacers than does the final structure 70
depicted in FIG. 7A.

[0110] In one embodiment, the first selective removal step of FIG. 6B is
not performed and the second selective removal step removes a polymer B
structure, resulting in the topography feature (substructure S) remaining
in the final structure 81 depicted in FIG. 8B which is analogous to the
Space Shrinkage structure in FIG. 4A.

[0111] In one embodiment, the first selective removal step of FIG. 6B is
not performed and the second selective removal step removes a polymer A
structure (as in the alternative embodiment of FIG. 6B described supra),
resulting in the topography feature (substructure S) remaining in the
final structure 91 depicted in FIG. 9B which is analogous to the Pattern
Doubling structure in FIG. 4A.

"Slimming Between" Process

[0112]FIG. 6C depicts a "slimming between" process in which a slimming
solvent (or another removal process such as a plasma etch) is used after
a first selective removal step, and before a second selective removal
step, to reduce the height of a polymer A structure (in the direction 21)
which reduces the aspect ratio of a polymer A structure with respect to
the exterior surface of the substrate. The slimming step in FIG. 6C
serves to reduce the height in direction 21 of a polymer A structure,
resulting in a shorter polymer A structure with a reduced aspect ratio.
In one embodiment, the height of a polymer B structure in direction 21 is
also reduced in the slimming step of FIG. 6C. The two selective removal
steps (e.g., wet development steps) are performed to selectively remove
the topography feature (substructure S) in the first selective removal
step and then (after the slimming step) to selectively remove a polymer B
structure in the second selective removal step, which results in the
polymer A spacer pattern of the final structure 62 in FIG. 6C that has
shorter spacers than in the final structure 60 depicted in FIG. 6A.

[0113] Although FIG. 6C depicts the slimming step being performed after
selective removal of the topographic substructures S is performed in the
first selective removal step and before the selective removal of polymer
B structures is performed in the second selective removal step, in one
embodiment the slimming step is performed after the selective removal of
polymer B structures is performed and before the selective removal of the
topographic substructures S is performed (i.e., the sequence of steps may
interchange the first and second selective removal steps).

[0114] An alternative embodiment with respect to FIG. 6C is to reduce the
height of a polymer B structure (or of both polymer B and polymer A
structures) in the slimming step and selectively remove a polymer A
structure (instead of a polymer B structure) in the second selective
removal step, which results in the polymer B spacer pattern in the final
structure 72 depicted in FIG. 7C instead of the polymer A spacer pattern
in the final structure 62 depicted in FIG. 6C. The final structure 72
depicted in FIG. 7C has shorter spacers than does the final structure 70
depicted in FIG. 7A.

[0115] In one embodiment, the first selective removal step of FIG. 6C is
not performed and the second selective removal step removes a polymer B
structure, resulting in the topography feature (substructure S) remaining
in the final structure 82 depicted in FIG. 8C which is analogous to the
Space Shrinkage structure in FIG. 4A. This embodiment resulting in the
final structure 82 depicted in FIG. 8C is the exact same process that has
resulted in the final structure 81 depicted in FIG. 8B, due to the first
selective removal step not being performed (i.e., the distinction between
"slimming first" and "slimming between" has disappeared).

[0116] In one embodiment, the first selective removal step of FIG. 6C is
not performed and the second selective removal step removes a polymer A
structure (as in the alternative embodiment of FIG. 7C described supra),
resulting in the topography feature (substructure S) remaining in the
final structure 92 depicted in FIG. 9C which is analogous to the Pattern
Doubling structure in FIG. 4A. This embodiment resulting in the final
structure 92 depicted in FIG. 9C is the exact same process that has
resulted in the final structure 91 depicted in FIG. 9B, due to the first
selective removal step not being performed (i.e., the distinction between
"slimming first" and "slimming between" has disappeared).

"Slimming Together" Process

[0117] FIG. 6D depicts a "slimming together" process in which a "slimming
together" step is performed after a first selective removal step is
performed. The first selective removal step (e.g., a wet development
step) selectively removes the topography feature (substructure S). In the
"slimming together" step, a mixture of the slimming solvent for polymer A
and the developer for polymer B is applied to simultaneously selectively
remove a polymer B structure and reduce the height of a polymer A
structure in the direction 21 to reduce the aspect ratio of a polymer A
structure with respect to the exterior surface of the substrate. The
slimming aspect of the "slimming together" step in FIG. 6D serves to
reduce the height of a polymer A structure, resulting in a shorter a
polymer A structure with a reduced aspect ratio. The polymer A spacer
pattern in the final structure 63 depicted in FIG. 6D resulting from the
"slimming together" step has shorter spacers than the spacers in the
final structure 60 depicted in FIG. 6A.

[0118] An alternative embodiment for FIG. 6D is to perform the "slimming
together" step such that a mixture of the slimming solvent for polymer B
and the developer for polymer A is applied to simultaneously selectively
remove polymer A and reduce the height of a polymer B structure in the
direction 21 to reduce the aspect ratio of a polymer B structure. In the
alternative embodiment, the slimming aspect of the "slimming together"
step serves to reduce the height of a polymer B structure, resulting in a
shorter polymer B structure with a reduced aspect ratio. The polymer B
spacer pattern in the final structure 73 resulting from the "slimming
together" step is depicted in FIG. 7D and has shorter spacers than has
the final structure 70 depicted in FIG. 7A.

[0119] In one embodiment, the first selective removal step of FIG. 6D is
not performed and the second selective removal step slims a polymer A
structure and selectively removes a polymer B structure, resulting in the
topography feature (substructure S) remaining in the final structure 83
depicted in FIG. 8D which is analogous to the Space Shrinkage structure
in FIG. 4A.

[0120] In one embodiment, the first selective removal step of FIG. 6D is
not performed and the second selective removal step slims a polymer B
structure and selectively removes a polymer A structure (as in the
alternative embodiment of FIG. 7D described supra), resulting in the
topography feature (substructure S) remaining in the final structure 93
depicted in FIG. 9D which is analogous to the Pattern Doubling structure
in FIG. 4A.

[0121] In the slimming schemes of FIGS. 6B-6D, 7B-7D, 8B-8D, and 9B-9D,
the slimming process decreases the aspect ratios of polymer features and
therefore significantly reduces pattern collapse.

[0122] If the slimming step is performed chemically by using a slimming
solution, then the slimming solution may selectively remove material from
both the top surface and exposed side surfaces of a polymer B structure
(or a polymer A structure in the alternative embodiments) in the slimming
steps of FIGS. 6B-6D. Since removing material from the side surfaces of
the polymer structure counteracts the benefit of removing material from
the top surface of the polymer structure with respect to its aspect
ratio, the parameters of the slimming step, which include the time
duration of the slimming step, should be controlled to ensure that the
resultant aspect ratio is within acceptable limits.

[0123] The slimming solution may comprise water, acids, bases, monohydric
alcohols, polyhydric alcohols, polyhydric alcohol partial ethers,
ketones, amides, ethers, esters, carbonates, aliphatic hydrocarbons,
aromatic hydrocarbons, and halogen-containing solvents. The slimming
solution may comprise the aforementioned solvents either individually, or
in a combination of two or more. In addition, other parameters including
volatility, flash point, swelling, and other properties should be
considered. The composition of the slimming solution should be chosen so
the desired selectivity in terms of the dissolution rate of the selected
polymer structure vis-a-vis the other polymer structures and
substructures is obtained. The slimming solution may also comprise
additives such as surfactants, stabilizers, anti-foaming agents, and the
like necessary to improve performance and minimize defectivity.

[0124] In one embodiment, the slimming solvent may comprise an acid
selected from the group of acetic acid, trifluoroacetic acid,
methanesulfonic acid, trifluoromethanesulfonic acid,
perfluorobutanesulfonic acid, p-toluenesulfonic acid, sulfuric acid,
nitric acid, hydrochloric acid, hydrofluoric acid, and the like. The acid
concentration may be adjusted by dilution with a non-acidic solvent such
as water (e.g., dilute aqueous hydrofluoric acid).

[0125] In one embodiment, the slimming solvent may comprise a base
selected from the group consisting of ammonium hydroxide,
tetramethylammonium hydroxide, tetrabutylammonium hydroxide, and the
like.

[0131] In another embodiment, the slimming solvent may comprise an amide
selected from the group consisting of N,N-dimethylimidazolidinone,
N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide,
acetamide, N-methylacetamide, N,N-dimethylacetamide,
N-methylpropionamide, and N-methylpyrrolidone and the like. These amide
solvents may be used either individually, or in a combination of two or
more.

[0134] In another embodiment, the slimming solvent may comprise an
aliphatic hydrocarbon selected from the group consisting of n-pentane,
iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane,
2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane,
methylcyclohexane, and the like. These aliphatic hydrocarbon solvents may
be used either individually, or in a combination of two or more.

[0135] In another embodiment, the slimming solvent may comprise an
aromatic hydrocarbon solvent selected from the group consisting of
benzene, toluene, xylene, ethylbenzene, trimethylbenzene,
methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene,
iso-butylbenzene, triethylbenzene, di-1-propylbenzene, n-amylnaphthalene,
trimethylbenzene, and the like. These aromatic hydrocarbon solvents may
be used either individually, or in a combination of two or more.

[0136] In another embodiment, the slimming solvent may comprise a
halogen-containing solvent selected from the group consisting of
dichloromethane, chloroform, fluorocarbon, chlorobenzene,
dichlorobenzene, and the like. These halogen-containing solvents may be
used either individually, or in a combination of two or more.

[0137] In one embodiment, the slimming process is stopped by rapidly
spinning the wafer to remove the developing solvent. In another
embodiment the slimming process is stopped by removing the developing
solvent by the application of a lower quality solvent or a non-solvent
for the material being removed by the slimming process. This application
can be accomplished by spraying or puddling the lower quality solvent on
the substrate, by dipping/immersing the substrate in the lower quality
solvent, or by combinations thereof.

[0138] In one embodiment, a plasma etch, instead of a chemical etch, may
be used to perform the slimming step anisotropically such that only the
top exposed surface (and not the side surfaces) of the polymer are
etched. Many suitable, plasma etching and reactive ion etching processes
are known in the literature. Dry etching conditions can be applied as
described in the art to achieve anisotropic removal of material. Polymer
structures can be etched by various plasmas generated from reactive gases
(such as O2, CF4) and/or noble gases (such as argon, helium).
The etch rate can be adjusted by the plasma composition, power, and
voltage, thereby enabling adjustment of the final aspect ratio of the
polymer structure. It should be noted that the etch rate of the polymer
in the plasma is dependent on the composition of the polymer. For
example, inorganic-containing polymers (such as silicon-containing
polymers) have lower etch rates in oxygen plasma than purely organic
polymers. For any given polymer material, the etch conditions (time,
power, voltage, and plasma composition) should be adjusted to render
polymer structures of proper aspect ratios.

[0139] The threshold aspect ratio, which is a demarcation line between a
polymer structure in the final structure (i.e., structures 61-63 in FIGS.
6B-6D; structures 71-73 in FIGS. 7B-7D; structures 81-83 in FIGS. 8B-8D;
structures 91-93 in FIGS. 9B-9D), depends on the material of the polymer
and the polymer pitch (i.e., the distance between successive polymers in
the direction 22) due to the capillary force during the second selective
removal step that draws successive polymers together. For example, for
large features (i.e., large pitch) a 3:1 aspect ratio may be acceptable
for mechanical stability, but if the pitch is small (e.g., 28 nm) the
threshold aspect ratio may be less than 1.5:1.

[0140] The stress by capillary force, which can cause pattern collapse,
can be decreased by increasing the space between patterned features or by
decreasing the aspect ratio of the patterned features. Since the former
method is impractical given the need for ever denser patterns with
smaller lateral feature sized, this means that a smaller aspect ratio is
needed for making smaller pitch patterns. The desirable aspect ratio is
roughly under 4 for 120-nm pitch patterns, 3 for 80-nm pitch patterns,
and 2 for 40-nm pitch patterns. Of course, these values also depend upon
the pattern geometry, the mechanical modulus of the patterned features,
adhesion of the patterned features to the underlying substrate, and other
factors. However, an aspect ratio of 1.5 or less is needed for 30-nm or
less pitch patterns.

[0142] Since the vertical aspect ratio of the polymer features are reduced
in the present invention, there is less material (e.g., a smaller
vertical thickness of the patterned material) remaining to serve as a
etch barrier during pattern transfer to the substrate 101 of any of the
spacer patterns of FIGS. 7B-7D, 8B-8D, 9B-9D. If the vertical thickness
of the material is reduced too much, an insufficient thickness will exist
for the polymer pattern to serve as an etch barrier during pattern
transfer. That is, the polymer pattern will be entirely consumed by the
etch process prior to completion of the pattern transfer process.
Therefore, it may be advantageous to use a polymer with an increased etch
resistance relative to that of the underlying substrate to compensate for
the reduced vertical aspect ratio. For example, when the substrate is an
organic material, the use of a polymer with a high concentration of a
refractory oxide-forming element such as silicon or germanium enables the
pattern to be transferred into the underlying organic material using an
oxygen-based plasma etch process. Increasing the silicon (or germanium)
content in the polymer increases its resistance to oxygen plasma and
allows thinner layers of polymer to be used in the pattern transfer
process.

[0143] In one embodiment, the first polymer and/or second polymer is
selected from the group consisting of a silicon-containing polymer which
is obtained by the hydrolysis and condensation of at least one
hydrolyzable silane compound selected from a hydrolyzable silane compound
shown by the following formula (1) (hereinafter referred to from time to
time as "compound (1)"), a hydrolyzable silane compound shown by the
following formula (2) (hereinafter referred to from time to time as
"compound (2)"), and a hydrolyzable silane compound shown by the
following formula (3) (hereinafter referred to from time to time as
"compound (3)").

RaSi(OR1)4-a (1)

wherein R represents a fluorine atom, a linear or branched alkyl group
having 1 to 5 carbon atoms, an alkenyl group having 2 to 6 carbon atoms,
or an alkylcarbonyloxy group, R1 represents a monovalent organic
group, and a represents an integer from 1 to 3,

Si(OR2)4 (2)

wherein R2 represents a monovalent organic group.

R3x(R4O)3-xSi--(R7)z-Si(OR5)3-yR6y
(3)

wherein R3 and R6 individually represent a fluorine atom, an
alkylcarbonyloxy group, or a linear or branched alkyl group having 1 to 5
carbon atoms, R4 and R5 individually represent a monovalent
organic group, x and y individually represent a number from 0 to 2, and
R7 represents an oxygen atom, a phenylene group, or a group
--(CH2)m-- (wherein m represents an integer from 1 to 6), and z
represents 0 or 1.

[0148] FIG. 13 is a flow chart describing a method for processing
structures, in accordance with embodiments of the present invention. The
method of FIG. 13 includes steps 41-44.

[0149] Step 41 forms a structural configuration that comprises a
substrate, a substructure having a sidewall and disposed on an external
surface of the substrate, a first polymer structure disposed on the
external surface of the substrate and in direct mechanical contact with
the sidewall, and a second polymer structure disposed on the external
surface of the substrate and in direct mechanical contact with the first
polymer structure such that the first polymer structure is disposed
between the sidewall and the second polymer structure. The first polymer
structure comprises a first polymer and the second polymer structure
comprises a second polymer. The substructure, first polymer structure,
and second polymer structure are in direct mechanical contact with the
external surface of the substrate. Step 41 may be performed in accordance
with the method described infra in FIG. 14.

[0150] Step 42 reduces an aspect ratio of each polymer structure of at
least one polymer structure with respect to the external surface of the
substrate. Said reducing comprises removing an upper portion furthest
from the substrate of each polymer structure of the at least one polymer
structure. The at least one polymer structure is selected from the group
consisting of the first polymer structure, the second polymer structure,
and both the first polymer structure and the second polymer structure. In
one embodiment, the at least one polymer structure is the first polymer
structure or the second polymer structure. In one embodiment, the at
least one polymer structure is the first polymer structure and the second
polymer structure.

[0151] Step 43 selectively removes one polymer structure from the
structural configuration such that a remaining polymer structure remains
disposed on the external surface of the substrate after the one polymer
structure has been selectively removed. Either the selectively removed
one polymer structure is the first polymer structure and the remaining
polymer structure is the second polymer structure or the selectively
removed one polymer structure is the second polymer structure and the
remaining polymer structure is the first polymer structure. Regardless of
which polymer structure is selectively removed, the remaining polymer
structure should have had its aspect ratio reduced in the slimming step
42.

[0152] In a first embodiment of the method of FIG. 13, the selectively
removed one polymer structure is the second polymer structure and the
remaining polymer structure is the first polymer structure, wherein the
method further comprises: selectively removing the substructure such that
the remaining polymer structure remains disposed on the external surface
of the substrate after the substructure has been selectively removed, as
depicted after the second selective removal in FIGS. 6B, 6C, and 6D.

[0153] In a first aspect of the preceding first embodiment corresponding
to the "slimming first" of FIG. 6B, said reducing the aspect ratio is
performed before said selectively removing one polymer structure is
performed and before said selectively removing the substructure is
performed, wherein either said selectively removing the substructure is
performed before said selectively removing one polymer structure is
performed or said selectively removing one polymer structure is performed
before said selectively removing the substructure is performed.

[0154] In a second aspect of the preceding first embodiment corresponding
to the "slimming between" of FIG. 6C, said selectively removing the
substructure is performed before said reducing the aspect ratio is
performed, and said reducing the aspect ratio is performed before said
removing one polymer structure is performed.

[0155] In a third aspect of the preceding first embodiment corresponding
to the "slimming together" of FIG. 6D, said selectively removing the
substructure is performed before said reducing the aspect ratio is
performed and before said removing one polymer structure is performed,
and said reducing the aspect ratio and said removing one polymer
structure are performed simultaneously.

[0156] In a second embodiment of the method of FIG. 13, the selectively
removed one polymer structure is the first polymer structure and the
remaining polymer structure is the second polymer structure, and wherein
the method further comprises: selectively removing the substructure such
that the remaining polymer structure remains disposed on the external
surface of the substrate after the substructure has been selectively
removed, as depicted in FIGS. 7B, 7C, and 7D.

[0157] In a first aspect of the preceding second embodiment corresponding
to the "slimming first" of FIG. 7B, said reducing the aspect ratio is
performed before said selectively removing one polymer structure is
performed and before said selectively removing the substructure is
performed, wherein either said selectively removing the substructure is
performed before said selectively removing one polymer structure is
performed or said selectively removing one polymer structure is performed
before said selectively removing the substructure is performed.

[0158] In a second aspect of the preceding second embodiment corresponding
to the "slimming between" of FIG. 7C, said selectively removing the
substructure is performed before said reducing the aspect ratio is
performed, and said reducing the aspect ratio is performed before said
removing one polymer structure is performed.

[0159] In a third aspect of the preceding second embodiment corresponding
to the "slimming together" of FIG. 7D, said selectively removing the
substructure is performed before said reducing the aspect ratio is
performed and before said removing one polymer structure is performed,
and said reducing the aspect ratio and said removing one polymer
structure are performed simultaneously.

[0160] In a third embodiment of the method of FIG. 13, the selectively
removed one polymer structure is the second polymer structure and the
remaining polymer structure is the first polymer structure, wherein the
substructure remains disposed on the external surface of the substrate
after the one polymer structure has been selectively removed, as depicted
in FIGS. 8B, 8C, and 8D.

[0161] In a first aspect of the preceding third embodiment corresponding
to the "slimming first or "slimming between" of FIG. 8B or 8C,
respectively, said reducing the aspect ratio is performed before said
selectively removing one polymer structure is performed.

[0162] In a second aspect of the preceding third embodiment corresponding
to the "slimming together" of FIG. 8D, said reducing the aspect ratio and
said removing one polymer structure are performed simultaneously.

[0163] In a fourth embodiment of the method of FIG. 13, the selectively
removed one polymer structure is the first polymer structure and the
remaining polymer structure is the second polymer structure, and wherein
the substructure remains disposed on the external surface of the
substrate after the one polymer structure has been selectively removed,
as depicted in FIGS. 9B, 9C, and 9D.

[0164] In a first aspect of the preceding fourth embodiment corresponding
to the "slimming first or "slimming between" of FIG. 9B or 9C,
respectively, said reducing the aspect ratio is performed before said
selectively removing one polymer structure is performed.

[0165] In a second aspect of the preceding fourth embodiment corresponding
to the "slimming together" of FIG. 9D said reducing the aspect ratio and
said removing one polymer structure are performed simultaneously.

[0166] FIG. 14 is a flow chart describing a method for forming the
structural configuration in step 41 of FIG. 13, in accordance with
embodiments of the present invention. The method of FIG. 13 includes
steps 51-52.

[0167] Step 51 applies a solution comprising the first polymer and the
second polymer to the substructure disposed on and in direct mechanical
contact with the substrate. The sidewall comprises a first material. A
selective chemical affinity of the first polymer for the first material
is greater than a selective chemical affinity of the second polymer for
the first material.

[0168] Step 52 segregates the first polymer from the second polymer,
wherein the first polymer selectively segregates to the sidewall
resulting in the first polymer being disposed between the sidewall and
the second polymer to form the structure in step 41 of FIG. 13.

Example 4

Slimming First Scheme

[0169] FIG. 10A shows the slimming first scheme of FIG. 6B, in accordance
with embodiments of the present invention. The topographical guiding
structures for the polymer blend are AR2928JN (JSR) resist patterns on
ARC29A (Brewer Science) with 110 nm half-pitch and 130 nm film thickness.
The patterned substrates are flood exposed using broad band UV with a
dose of 100 mJ/cm2 and then baked at 115° C. for 60 seconds
and 185° C. for 120 seconds to switch the polarity of the resist
and harden the resist to PGMEA. A 1.5 wt % PGMEA solution of AcOMBS
(poly(1-(4-acetoxyphenyl)ethyl silesquioxane)) and PS (polystyrene, 22k)
with the weight ratio of 50:50 was spin-cast on the treated resist
substructure S (see FIG. 4A) at 3000 rpm for 30 seconds and then baked at
100° C. for 60 seconds and the polymer blend to form segregated
structures within the resist trench. AcOMBS (polymer A--see FIG. 4A)
segregates to the sidewall of the resist features and PS (polymer B--see
FIG. 4A) segregates to the center of the trench. The slimming process is
applied before development of resist and PS. In the slimming step, the
sample is dipped in the slimming solvent for 60 seconds. The slimming
step is stopped by rinsing the sample with water (a non-solvent for
treated resist, PS and AcOMBS). After rinse, the sample is spin-dried.
After the slimming process, the treated resist features were selectively
removed by 0.26N TMAH, and PS was selectively removed by cyclohexane.
With proper slimming solvent, the pattern profile of AcOMBS is improved
and pattern collapse is reduced.

[0170] FIG. 10B is the cross-section SEM images of the AcOMBS lines formed
using the reference process shown in FIG. 6A, in accordance with
embodiments of the present invention. The depicted AcOMBS lines pertain
to after selective removal of the resist and PS without the slimming
process. Some AcOMBS lines collapse and other AcOMBS lines do not form
perpendicular to the substrate and bend toward the space which was
occupied by the treated resist.

[0171] FIGS. 10C to 10G are the cross-section SEM images of the final
AcOMBS lines formed using the slimming first scheme in FIG. 10A, in
accordance with embodiments of the present invention. Various slimming
solvents are used for slimming process. Methanol is a good solvent for
AcOMBS, a poor solvent for the treated resist, and a non-solvent for PS
and resist features. A mixture of methanol (MeOH) and water is used to
show the slimming results. Water is a non-solvent for treated resist, PS
and AcOMBS. A mixture solvent of MeOH and water gives a range of solvent
properties as a function of mixing ratio. Mixture solvents of
MeOH:H2O=80:20 (wt/wt) and MeOH:H2O=80:20 (wt/wt) reduce the aspect ratio
of the AcOMBS lines but do not completely correct the bending of the
AcOMBS lines as shown in FIG. 10C and FIG. 10D. A mixture solvent of
MeOH:H2O=90:10 (wt/wt) reduces the aspect ratio of AcOMBS lines and
render vertical sidewalls of AcOMBS lines (FIG. 10E). If MeOH content is
further increased in the mixture solvent, the solubility of AcOMBS lines
in the solvent become too high for the slimming purpose. For example, the
larger thickness variation in AcOMBS lines is observed after applying a
slimming solvent of MeOH:H2O=95:5 (wt/wt) as shown in FIG. 10F. FIG. 10G
shows almost all of the AcOMBS lines are dissolved in a slimming solvent
using MeOH alone.

Example 5

Slimming Between Scheme

[0172] FIG. 11A shows the slimming between scheme of FIG. 6C, in
accordance with embodiments of the present invention. The topographical
guiding structures for polymer blend are AR2928JN (JSR) resist patterns
on ARC29 (Brewer Science) with 110 nm half-pitch and 130 nm film
thickness. The patterned substrates are flood exposed using broad band UV
with a dose of 100 mJ/cm2 and then baked at 115° C. for 60
seconds and 185° C. for 120 seconds to switch the polarity of the
resist and harden the resist to PGMEA. A 1.5 wt % PGMEA solution of
AcOMBS and PS (polystyrene, 22k) with the weight ratio of 50:50 was
spin-cast on the treated resist substructure S (see FIG. 4A) at 3000 rpm
for 30 seconds and then baked at 100° C. for 60 seconds and to
form segregated structures within resist trench. AcOMBS (polymer A--see
FIG. 4A) segregates to the sidewall of the resist features and PS
(polymer B--FIG. 4A) segregates to the center of the trench. After
segregation, the treated resist features were selectively removed by
0.26N TMAH. The slimming process is applied in between the development of
resist and development of PS. In the slimming step, the sample is dipped
in the slimming solvent for 60 seconds. The slimming step is stopped by
rinsing the sample with water (a non-solvent for treated resist, PS and
AcOMBS). After rinse, the sample is spin-dried. After the slimming
process, PS is selectively removed by cyclohexane. With proper slimming
solvent, the pattern profile of AcOMBS is improved and pattern collapse
is reduced.

[0173] FIGS. 11B and 11E shows cross-section SEM images of 100K and 20K
magnification, respectively, of the AcOMBS lines formed using the
reference process shown in FIG. 6A, in accordance with embodiments of the
present invention. The depicted AcOMBS lines pertain to after selective
removal of the resist and PS without the slimming process. Some AcOMBS
lines collapse and other AcOMBS lines do not form perpendicular to the
substrate and bend toward the space which was occupied by the treated
resist.

[0174]FIG. 11C and FIG. 11F shows cross-section SEM images of 100K and
20K magnification, respectively, of the AcOMBS lines for the slimming
between scheme of FIG. 11A using IPA as a slimming solvent, in accordance
with embodiments of the present invention. The depicted AcOMBS lines
pertain to after (i) selective removal of resist line, (ii) slimming
process and then (iii) selective removal of resist and PS features. Two
different slimming solvents are used for slimming process. IPA is used as
a slimming solvent and reduces aspect ratio of the AcOMBS lines, but
there are still few spots with collapse lines in the 20K magnification
SEM image. No pattern collapse is observed in the 20K magnification SEM.

[0175] FIG. 11D and FIG. 11G shows cross-section SEM images of 100K and
20K magnification, respectively, of the AcOMBS lines for the slimming
between scheme of FIG. 11A using a mixture solvent of MeOH:H2O=80:20, in
accordance with embodiments of the present invention. The depicted AcOMBS
lines pertain to after (i) selective removal of resist line, (ii)
slimming process and then (iii) selective removal of resist and PS
features. Two different slimming solvents are used for slimming process.
A mixture solvent of MeOH:H2O=80:20 (wt/wt) reduces aspect ratio of
AcOMBS lines and renders vertical sidewalls of AcOMBS lines. No pattern
collapse is observed in the 20K magnification SEM.

Example 6

Slimming Together Scheme

[0176] FIG. 12A shows the slimming together scheme of FIG. 6D, in
accordance with embodiments of the present invention. The topographical
guiding structures for polymer blend are AR2928JN (JSR) resist patterns
on ARC29 (Brewer Science) with 110 nm half-pitch and 130 nm film
thickness. The patterned substrates are flood exposed using broad band UV
with a dose of 100 mJ/cm2 and then baked at 115° C. for 60
seconds and 185° C. for 120 seconds to switch the polarity of the
resist and harden the resist to PGMEA. A 1.5 wt % PGMEA solution of
AcOMBS and PS (polystyrene, 22k) with the weight ratio of 50:50 was spin
casted on the treated resist substructure S (see FIG. 4A) at 3000 rpm for
30 seconds and then baked at 100° C. for 60 seconds and the
polymer blend to form segregated structures within resist trench. AcOMBS
(polymer A--see FIG. 4A) segregates to the sidewall of the resist
features and PS (polymer B--see FIG. 4A) segregates to the center of the
trench. After segregation, the treated resist features were selectively
removed by 0.26N TMAH. The slimming process is applied together with the
development of PS. In the slimming/development step, the sample is dipped
in the slimming/developing solvent for 60 seconds. The
slimming/development step is stopped by rinsing the sample with water (a
non-solvent for treated resist, PS and AcOMBS). After rinse, the sample
is spin-dried. With proper slimming/development solvent, the pattern
profile of AcOMBS is improved and pattern collapse is reduced.

[0177] FIG. 12B shows cross-section SEM images of AcOMBS lines formed
using the reference process shown in FIG. 6A after selective removal of
the resist and PS without the slimming process, in accordance with
embodiments of the present invention. Some AcOMBS lines collapse and
other AcOMBS lines do not form perpendicular to the substrate and bend
toward the space which was occupied by the treated resist.

[0178] FIG. 12C shows cross-section SEM images of AcOMBS lines after
selective removal of resist line followed by a slimming/developing step
of FIG. 12A using a mixture solvent of cyclohexane:acetone=96:4 (wt/wt),
in accordance with embodiments of the present invention. The AcOMBS lines
completely collapsed on the substrate. This mixture solvent swells AcOMBS
and does not remove AcOMBS cleanly.

[0179] FIG. 12D shows cross-section SEM images of AcOMBS lines after
selective removal of resist line followed by a slimming/developing step
of FIG. 12A using a mixture solvent of cyclohexane:acetone=98:2 (wt/wt),
in accordance with embodiments of the present invention. The aspect ratio
of the AcOMBS line is reduced and no pattern collapse of AcOMBS lines is
observed.

[0180] While embodiments of the present invention have been described
herein for purposes of illustration, many modifications and changes will
become apparent to those skilled in the art. Accordingly, the appended
claims are intended to encompass all such modifications and changes as
fall within the true spirit and scope of this invention.

Patent applications by Daniel P. Sanders, San Jose, CA US

Patent applications by Joy Cheng, San Jose, CA US

Patent applications by International Business Machines Corporation

Patent applications by JSR Corporation

Patent applications in class ETCHING AND COATING OCCUR IN THE SAME PROCESSING CHAMBER

Patent applications in all subclasses ETCHING AND COATING OCCUR IN THE SAME PROCESSING CHAMBER